Polysaccharide derivatives of substituted dicarboxylic acids



Patented Dec. 1, 1953 POLYSAGCHARIDE DERIVATIVES OF SUB- STITUTED 'DICABBOXYLIC ACIDS Carlyle G. Cfldwe'll, Forest Hills, and Otto B. Wurzhurg,Babylon, N. Y., assignors to National :Starch Products 1110., New York, N. Y., a corporation of Delaware 'No Drawing. Application February '18, 1949, Serial No. 77,296

3 Claims.

Qur invention relates to new derivatives of polysaccharides. More 'particularlyit is our ob root to produce derivatives of starch, character- ;ized by greatly improved qualities as emulsifying agents, thic'keners, sizes, and other commercial applications.

It is generally recognized that an emulsifying chemicalis one which commonly contains within its structure both a hydrophobic and a hydrophilic radical. It is, therefore, .our further object to devise a commercially economical process whereby 'a hydrophilic group as well as a hydrophobic group may be introduced into a polysaccharide molecule, and, specifically, it is our object to produce a substituted ,polysaccharide wherein each :substituent radical contains both a hydrozphilicsand ;a.hydrop'hobic group.

Ordinary surfaceactiv.e agents:as, for 8X- ample, soaps-which are effective as emulsifiers,

are characterized by having in each molecule :both

a .hydrophilic group and a hydrophobic group. These molecules, when dispersed inran agitated oil and water mixture, are believed to orient themselves more or less perpendicularly to the interface of the water and oil droplets, the hydrophobic portion being in the oil phase and the :hydrophilic portion being in the Water phase, with the result that a monomolecular film of the emulsifier molecules is formed about each droplet.

These films have very low cohesive forces and the molecules in them are heldin place primarily because of the forcesexerted :by the oil and water phases. {They are easily disrupted, with the result that oil droplets may be caused to coalesce to form Elarger aggregates, :and continuation of this-process may eventually result in a separation of the emulsion into two phases.

On the other :hand, polysaccharides such as starch or cellulose are high moleculaI-weight'filmformingsmaterials. .Suchproductspwh'en treated so that their molecules contain hydrophobic :as well as hydrophilic groups'likewise tend to be attracted to the interface of water and oil droplets in an emulsion. However, since these molecules are linear, or appreciably so, and the .hydrophilic and hydrophobic groups are distributed along the linear polymeric molecules, orientation of these linear molecules must be more or less parallel to the interface to allow the hydrophobic groups to extend into the oil phase and the hydrophilic 5 2 that such .a polysaccharide derivative tends to give more stable and permanent emulsions In copending application, .Serial No. 4,9.47,'filed January28, 1948, there is described a method for forming mixed .ethers of polysaccharides wherein one ether linkage introduces a hydrophilic group and the other ether linkage introduces a hydrophobic group. Although such products are good emulsifying agents, for the reasons explained above their manufacture involves a rather complex procedure, including the use of at least two separate etherifying reagents (one to introduce the hydrophilic group and one to introduce the hydrophobic group)..

We have .now discovered that products which are .even better for many purposes, can be pro- .clucedmore simplyv and economically. Our inventioncomprises the treatment of a polysaccharide with ,a single reagent which introduces both a'hydrophilicand a hydrophobic group, so that each substituent radical of the resultant substituted .polysaccharideicontains both ahydrophilic as well as .ahydrophobic group. By the previous method, described .above, one substituent radical could contain a .hydrophilic group and another could contain .a hydrophobic group, but ,no one substituent radical could contain both.

The product of our invention is valuable for many industrial purposes, particularly because of its ability to form .more stable and permanent emulsions. It is believed that this improvement results irom the fact that both the hydrophilic and hydrophobic functions, in the productof our invention, are present in each substituentgroup and, thus, more uniformly balance each other. On theother'hand, in the above-mentioned mixed etherderivatives, there .is probably a more heterogeneous distribution of hydrophilic and hydrophobic groups; 1. e., some portions of the ,polymeric chain contain a relative'lyhigh ratio of hydrophilic to hydrophobic groups, while other portions of the chain contain the reverse ratio. For the manufacture of our product, it is not necessary to use imore than one reagent, this one reagent introducing'both athydrophilie and ahydrophobic group. The economy involved in elimimating the use of at least one majorreagent (that is, :as compared to the minimum of two reagents required by the process of the copending application}, is self-evident.

In the term polysaccharide we mean to include starch, gelatinized or .ungelatinized, from sourceincluding corn, tapioca, potato, wheat, sage, r'ice,wvaxy maize, and the other known types; also modified or thin-boilingstarches and starch 3 erivatives; also dextrins; also cellulose (such s wood pulp, cotton linters, regenerated celluise), and hemi-cellulose, in the form of their 'ater-soluble derivatives.

According to our method, a polysaccharide is reated with a substituted cyclic dicarboxylic acid nhydride (hereafter sometimes called the regent) of the following structural formula:

'herein R, represents a dimethylene or trimethylne radical and wherein R is the substituent roup, which is a hydrophobic group (ordinarily long chain hydrocarbon radical). Substituted yclic dicarboxylic acid anhydrides falling with- 1 the above structural formula are the sub- ;ituted succinic and glutaric acid anhydrides.

The hydrophobic substituent group R may be lkyl, alkenyl, aralkyl, or aralkenyl, and should ontain from 5 to 18 carbon atoms. R may be )ined to the anhydride moiety B through a caron-to-carbon bond (as in alkenyl succinic an-' vydride) or through two carbon-to-carbon bonds as in the adduct of maleic anhydride with methyl entadiene, or as in the cyclo-parafiinic cycloicarboxylic acid anhydrides, such as, for exmple, cyclo hexane 1,2-dicarboxylic acid anhyride), or may be linked through an ether or ster linkage (as, for example, in octyloxy sucinic anhydride or in capryloxy succinic anhyride). Regardless of the particular linkage be- Ween the hydrophobic substituent R and the ,nhydride proper, all of the above-listed types all within the class substituted succinic or gluaric anhydrides. In place of the organic acid ,nhydrides mentioned above, one may also use he substituted dicarboxylic acid chlorides of hose dicarboxylic acids which form cyclic anlyclrides, such as, for example, alkenyl succinic .cid chloride. Therefore, in this specification and he examples and claims, it is to be understood hat whenever we speak of the organic acid anhylride, the substituted dicarboxylic acid chloride may be used as the equivalent thereof. In all ases, the remaining free carboxyl radical presnt after the reaction of the reagent with the mlysaccharide represents the hydrophilic group. The products formed by the reaction of polyaccharides with any of the above-listed reagents ,re the acid esters of the substituted dicarboxylic .cids and, more specifically, they are the acid sters of either substituted succinic or glutaric .cid. These acid esters may be represented by he following structural formula:

C O O H polysaccharide O 0 C -R-R' Jherein R is a dimethylene or trimethylene radial and R is the substituent hydrophobic group this being an alkyl, alkenyl, aralkyl, or aralkenyl :roup containing from 5 to 18 carbon atoms). The hydrophilic group in all cases is the remainng free carboxyl group (COOH) resulting from he esterification of only one carboxyl group of he dicarboxylic acid.

The esterification of the polysaccharide with he substituted cyclic organic acid anhydride may ake place in one of the following ways (it being llldBIStOOd that although we refer to starch, for

a the sake of brevity, there is no intent thereby to exclude the other polysaccharides) I. Aqueous method-43y this method the starch is treated, while in aqueous suspension, with the reagent.

In Patent No. 2,861,139, granted February 8, 1949, there is described a method for treating starch, in aqueous alkaline suspension, with an organic acid anhydride. Although that patent does not contemplate or disclose the use of a re agent which introduces a substituent containin within its structure both a hydrophilic and a hydrophobic group, the general procedure of that process may be followed in our present invention.

Thus, the pH of the suspension may be maintained on the alkaline side, preferably not lower than '7 nor higher than 11. This can be accomplished by adding enough of an alkaline medium, such as dilute sodium hydroxide or sodium carbonate solution, to the starch milk to raise the pHfor example, to 11and then to add one of the reagents from the above-listed groupsay, alkenyl succinic anhydrideuntil the pH is low ered to about '7. Alternate addition of alkali and anhydride reagent is continued in this manner until the desired amount of reagent has been added. Another method is to run the alkali and the anhydride reagent into the starch milk concurrently, regulating the rate of flow of each of these added materials so that the pH of the starch suspension remains preferably between 3 and 11. Still another method is to add concurrently the starch milk, alkali, and the anhydride reagent into a central vessel, with Vigorous agitation. By still another variation, the entire calculated amount of a suitable alkali is added to the starch milk at the beginning of the process, followed by the addition of the entire quantity of reagent, without any subsequent additions of either alkali or reagent.

The reaction is preferably carried out at room temperature,

The proportion of reagent to be used varies with the degree of substitution desired in the final product. However, for the aqueous and dry methods, we ordinarily prefer to use quantities ranging from 0.1% to about based on the dry starch content, and when the final product is to be in the form of an ungelatinized starch derivative, a maximum of about 10% of the anhydride reagent is often sufficient.

This same procedure may be applied to starches which have been gelatinized and dispersed, as well as to starch degradation products such as thin boiling starches, British gums, and dextrins, which, depending on their solubility or pretreatment, may undergo the reaction in a state of suspension, dispersion, or solution. When the reaction is complete, the product, if ungelatinized, may be filtered, washed with water, and dried, in the usual manner. If the starch or starch derivative has been gelatinized and/or dispersed, the final product may be used in the form of its aqueous dispersion or it may be dried by passing over heated drums, by spray drying or by precipitation in alcohol or other organic solvent media with subsequent drying of the precipitate.

It should be pointed out that whenever we refer to alkali in this specification, the word is meant to include not only sodium hydroxide, but also other basic chemicals, including the hydroxides or basic salts of sodium, potassium, barium, lithium, as well as quaternary ammonium hydroxides, and other organic bases.

Although we have referred to the products of our invention as polysaccharide acid esters, it will be obvious that because of the alkaline conditions prevailing during the reaction, the final product is ordinarily actually produced in the form of the sodium or other salt .of the acid ester. In other words, in the diagrammatic formula which we have shown for the polysaccharide acid ester, the carboxyl group COOH would ordinarily be present in the form of its salt. This holds true regardless of which re.- action method is used. If it is undesirable to have the acid ester in the form of its salt, the final product may be Washed with a dilute mineral acid in order that the salt of the carhoxyl group may be changed to the normal carboxyl form CGOH. Wherever, in the claims or specification, we refer to the polysaccharide acid ester, therefore, it will be understood that this term includes the salt of the acid ester.

II. Dry method-We have also found that the treatment of the starch with a reagent to in-- troduce a hydrophilic and hydrophobic group may be carried out with the starch in the com mercially dry form. By commercially dry we mean a starch having a moisture content of approximately to This is best done by blending the dry starch with an alkaline material such as trisodium phosphate or sodium carbonate and with the reagent (such as, for example, allzenyl succinic anhydride), and heating the Instead of blending the alkaline material with the dry starch, one may use a starch which has been pretreated by suspending it in water containing dissolved therein approximately 1% of sodium hydroxide or other strong base (calculated on the dry weight of the starch) followed by filtering without washing, and drying. This dry alkali-treated starch may then be reacted as above indicated, directly with the reagent. A specific illustration of this method will be found among the examples to be given at later point in this specification.

III. Organic suspension or dispersion method- In place of Method 1, wherein water is the suspension or dispersion medium, the starch may be treated in an organic liquid such as benzol, which is chemically inert toward the starch and the reagent. Thus, the ungelatinized starch may be suspended in benzol, with the subsequent addi on of the reagent together with sufficient pyridine (which is alkaline) to neutralize the reagent. The solvent may be removed, after the reaction, by distillation. By another variation, starch wh 1 has been pregeiatinized and dried is dispersed 'l pyridine, and the reagent added. It is ordinarily found that when using the organic dispersion method, it is advisable to use somewhat larger quantities of he anhydride reagent.

The following examples will further illustrate the embodiment of our invention:

EXAll/[PLE I This example illustrates the production of the starch acid ester of a substituted succinic acid wherein decenyl group is the alkenyl hydronhobic substituent corresponding to R in the structural formula the free carboxyl radical the hydrophilic group. In this, and in the other examples, all parts given are by weight.

Five (5) parts of sodium carbonate were (ii..- solyed i 59 parts of water. One hundred (100) parts of tapioca starch were suspended in this alkaline solution, with agitation, and this was followed by adding slowly 10 parts of deceuyl succinic acid anhydride. Agitation. was con tinued for 14 hours, at room temperature. The pH was then adjusted to 7.0, using dilute hydrochloric acid solution. The starch derivative was then filtered, washed with water, dried, and powdered.

The resulting product was a white powder resembling, in physical appearance, ordinary powdered starch To illustrate its emulsifying power, 4 grams of the starch derivative were cooked in t6 cos. of water for 1.5 minutes at 95 C. After cooling, grams of turpentine were added by means of a high-speed agitator. The result was an emulsion with .a 33 of oil phase. The emulsion was verysmooth, creamy white, with excellent stability. By contrast, when run treated tapioca starch was used as the emulsifying agent, under comparable conditions, the turpentine began to separate out immediately after agitation was stopped.

EXAMPLE II This example illustrates the production of the starch acid ester of a substituted succinic acid wherein the octenyl group is the alkenyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

Two '(2) parts of sodium carbonate were dissolved in 150 parts of water. To this solution was added, with agitation, 100 parts of a thinboiling corn starch (known as fluidity corn starch). This was followed by the addition of 0.1 part of octenyl succinic acid anhydride. Agitation was continued for 12 hours and, after adjusting the pH to approximately '7, the material was filtered, washed, and dried.

EXAIVLPLE III This example illustrates the production of the cellulose acid ester of a substituted succinic acid wherein the nonenyl group is the alkenyl hydrophobic substitu-ent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

In 12,000 parts of water there were dispersed 400 parts of .a water-soluble methyl cellulose (distributed by General Dyestuff Corporation under the trade .name Colloresine DKHV). To this dispersion was added a solution of 30 parts of sodium carbonate in 200 parts of water. Fifty (5.0) parts of nonenyl succinic acid anhydride were then added. Agitation was maintained for approximately 16 hours, whereupon the pH was adjusted to 6.5 by the addition of hydrochloric acid.

EXAMPLE IV This example illustrates the production of the starch acid ester of a substituted succinic acid wherein the triisobutenyl radical is the alkenyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

Six (6.0) parts of sodium carbonate were dissolved in 150 parts of water, and 100 parts of a thin-boiling waxy maize starch (known in the trade as fluidity waxy maize) was added thereto, with agitation. There were then added 10 parts of 'tri-isobutenyl succinic acid anhydride (dissolved in 46 parts of acetone). Agitation was continued for approximately 14 hours, followed by neutralization, filtration, washing, and drying. In this, as in the other examples, it was found that further purification could be achieved 7 y washing the material, during the filtration tep, not only with water but also with a wateriiscible chemical which acts as a solvent for the eagent. Thus, in this case, the starch derivative 'as washed with ethyl alcohol, followed by washig with water.

EXAMPLE V This example illustrates the production of the 'Jarch acid ester of a substituted succinic acid 'herein the octadecenyl group is the alkenyl ydrophobic substituent corresponding to R in ne structural formula and the free carboxyl rad- :al is the hydrophilic group.

One hundred (10G) parts of a heavy-cooking ipioca British gum (having a solubility of l00%) were dispersed in 100 parts of water. he pH of the dispersion was raised to 9.0 by the ddition of a 2% sodium hydroxide solution. hen there were added, slowly, with continuous gitation, parts of octadecenyl succinic acid nhydride dissolved in acetone. The pH was iaintained between 8 and 9 by further additions f dilute sodium hydroxide solution, as necessary. .gitation was continued for 10 hours, with the H being maintained at the 8-9 level. Then the H was adjusted to 6.5. It Wasfound that the esulting dispersion could be used, without fur- 181 treatment, as an emulsifying agent. In )me cases, it was found preferable to cook the ispersion for several minutes prior to its use. urther purification could be achieved by pourig the dispersion into a water-miscible organic )lvent such as ethyl alcohol or acetone, thereby recipitating the starch derivative, followed by 'ashing and drying. In another variation, aplicable to this as well as to the other examples, 1e dispersion or suspension of the starch deriva- .ve may be passed over revolving heated drums, zsulting in a gelatinized, dried product.

EXAIVIPLE VI This example illustrates the production of the ;arch acid ester of a substituted succinic acid herein the octenyl group is the alkenyl hydrohobic substituent corresponding to R in the ;ructural formula and the free carboxyl radical the hydrophilic group. As distinguished, howver, from Example V, this example illustrates 1e use of the acid chloride reagent rather than 1e anhydride.

One hundred (100) parts of potato starch were lspended in 150 parts of water. The pH was iised to 9 by the addition of a 3%solution of )dium hydroxide. There were then added, slow- I, with agitation, 10 parts of octenyl succinic cid chloride (maintaining the pH throughout 'ithin the range 7-10 by the addition, as necesiry, of a 3% sodium hydroxide solution). Agiition was continued for 10 hours, maintaining 1e pH at approximately 8. At the end of this eriod, the pH was lowered to '7 by the addition if dilute hydrochloric acid and the starch deriva- .ve was filtered, washed with water, and dried.

EXAMPLE VII This example illustrates the production of the ;arch acid ester of a substituted succinic acid herein the octenyl group is the alkenyl hydrohobic substituent corresponding to R. in the 3ructural formula and the free carboxyl radical the hydrophilic group.

Sne hundred (166) parts of an acid converted, am-boiling waxy maize starch (85 fluidity) were elatinized by cooking 'in 100 parts of water.

Upon cooling, the pH was brought to 9 by the addition of dilute sodium hydroxide solution. There were then added, slowly, with continuous agitation, parts of octenyl succinic acid anhydride (maintaining the pH during this addition of reagent at 8 by the addition, as necessary, of sodium hydroxide solution). Agitation was continued for approximately 7 hours, after which the pH was adjusted to '7 by the addition of hydrochloric acid. The resulting heavy, grayishwhite paste was found suitable for use as an emulsifying agent, without further treatment, although, if desired, it could, of course, be subjected to drying over heated drums or could be precipitated by mixing with a large excess of ethyl alcohol, acetone, or other known precipitants, followed by filtration and drying.

EXAlVlPLE VIII This example illustrates the production of the starch acid ester of a substituted succinic acid wherein the methyl pentadiene addendum is the alkenyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

Eight (8) parts of sodium carbonate were dissolved in parts of water. 100 parts of thinboiling corn starch (60 fluidity corn starch) were suspended therein, and this was followed by the slow addition of 10 parts of a 60% solution of the adduct of maleic anhydride with methyl pentadiene in dioxane. Agitation was continued for about 16 hours, followed by neutralization and filtration. It was found advisable, in order to achieve further purification, to wash with dioxane during the filtration step, followed by washing with water and drying.

EXAMPLE IX This example illustrates the production of the starch acid ester of a substituted succinic acid wherein the capryloxy radical is the alkyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

One hundred (100) parts of corn starch were suspended in 150 parts of water. The pH was adjusted to 10 by the addition of a 3% solution of sodium hydroxide. There were then added, slowly, 20 parts of capryloxy succinic acid anhydride (keeping the pH within the range of 7-10 by the addition, as necessary, of 3% sodium hydroxide solution). Agitation was continued for 10 hours, maintaining the pH at about 8. At the end of this period, the material was neutralized to pH '7 by the addition of dilute hydrochloric acid. The starch derivative was filtered, washed with water, and dried.

EXAMPLE X This example illustrates the production of the starch acid ester of a substituted succinic acid wherein the octenyl group is the alkenyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group. This example also illustrates the dry reaction method.

Ten parts of octenyl succinic acid anhydride were thinned by mixing with suflicient toluene to produce a liquid suitable for spraying. This material was then sprayed into 100 parts of corn starch into which there had previously been blended 6 parts of powdered sodium carbonate. This mixture was agitated for 3 days, maintaining the temperature within the range 90-1-00 F. Sufficient heat was then applied to the starch derivative to drive ofi residual toluene. By a variation of this method, 100 parts of corn starch were suspended in water in which had been dissolved 1 part of sodium hydroxide. The starch was then filtered and dried. Into this dry starch were then sprayed parts of octenyl succinic acid anhydride, which had been thinned as indicated above. The mixture was agitated and heated to the same extent as shown above.

EXAMPLE XI This example illustrates the production of the starch acid ester of a substituted succinic acid wherein the nonenyl group is the alkenyl hydrophobic substituent corresponding to R in the structural formula and the free carb'oxyl radical is the hydrophilic group. This example also illustrates the organic dispersion method.

Twenty (20) parts of starch were gelatinized by cooking in water and then precipitated by pouring the starch dispersion into a large excess of ethanol. The gelatinized starch precipitate was then filtered and dried. This dried, gelatinized starch was then dispersed in 200 parts of pyridine, and 172 parts of nonenyl succinic acid anhydride were added. The mixture was heated at IOU-120 C. for approximately 10 hours, then cooled, and poured into a large excess (approximately 3000 ml.) of ethanol. The resulting starch derivative precipitate was filtered, washed several times with ethyl alcohol to remove residual reagent, and dried. The white granular material resulting from this process is preferably prepared for use as an emulsifying agent by dispersing in a very dilute solution of sodium hydroxide or other alkali metal hydroxide, thus forming the alkali metal salt of the starch derivative.

EXAMPLE XII This example illustrates the production of the cellulose acid ester of a substituted succinic acid wherein the octenyl group is the alkenyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

In 12,000 parts of water there were dispersed 400 parts of a Water-soluble methyl cellulose (distributed by General Dyestufl Corporation under the trade name Colloresine DKHV). To this dispersion was added a solution of 30 parts of sodium carbonate in 230 parts of water. 50 parts of octenyl succinic acid anhydride were then added. Agitation was maintained for approximately 16 hours, whereupon the pH was adjusted to 6.5 by the addition of hydrochloric acid.

EXAMPLE XIII This example illustrates the production of the starch acid ester of a substituted glutaric acid wherein the heptyl group is the alkyl hydrophobic substituent corresponding to R in the structural formula and the free carboxyl radical is the hydrophilic group.

One thousand (1,000) parts of corn starch were suspended in 1,250 parts of water in which 80 parts of sodium carbonate had been dissolved. There were slowly added, with agitation, 100 parts of heptyl glutaric acid anhydride. Agitation was maintained for 18 hours, whereupon the pH was adjusted to 7.0, the starch product filtered, washed twice with water, and dried.

EXAMPLE XIV This example illustrates the production of the starch acid ester of a substituted succinic acid l u v wherein the benzylcxy radical is the aralkyl hydrophobic substituent corresponding to R3 in the structural formula and the free carboxyl radical m the hydrophi-lic group.

One thousand 1,000) parts of corn starch were suspended in 1 ,250 parts of water in which parts of sodium carbonate had been dissolved. There were slowly added, with agitation, lililp'arts of benzyloxy succinic acid anhydri'de'. After approximately 12 hours ofi agitation, the product was neutralized, filtered, washed, and dried.

The products of our invention, it permitted to undergo the reaction in their ung'elatinized state, may be'made ready for use as emulsifying agents by cooking in water to form a dispersion. If the products are produced in the form of a dispersion or solution, they may be used, if desired, without further treatment. Various methods of purification have already been indicated. The polysaccharide derivatives of our invention may be subjected to any of the physical and chemical reactions known tobe applicable to polysaccharides, such as treatment upon heat-ed drums, dextrinization, as well as treatment with chemicals. One such chemical treatment, for-example, involves the reaction of the starch derivative ofthis present inventionwith certain organic acidanhydrides, such as maleic acid anhydride (as described in U. S. Patent No. 2,461,139 of February 8, 1949), followed by the subsequent treatment with a reagent such as a bisulfite, to introduce sulfonic acid groups (as described in copending application Serial No. 756,106, filed June 20, 1947).

As already stated, the products of our invention have excellent properties as emulsifying agents, and specific use of this property will be apparent to those familiar with the art. Furthermore, our products are valuable as thickeners. Frequently, it is desirable to employ combination thickeners-emulsifiers, as, for example, in the manufacture of cold creams, resin emulsions, emulsion type paints, cleaning compounds, and the like.

Emulsion type paints ordinarily consist of emulsions of oils, resins, and/or lacquers in water. Since these products are ordinarily incompatible with water, it is necessary to use an emulsifying agent which will effectively stabilize the emulsion. Furthermore, consistency is an important factor in paints since either too great or too little ilow can seriously interfere with the utility of the paint. Therefore, is is necessary to employ thickening agents. The polysaccharide product of our invention combines these properties of thickener and emulsifier and is, therefore, of particular value for this application.

Cold creams and similar cosmetic preparations are ordinarily based upon oil and. water emulsions, and viscosity is an important factor, the products ranging from fiowable materials to salves and heavy pastes. Here, too, the polysaccharide derivative of our invention acts as a combination emulsifier-thickener.

Many liquid cleaning compounds consist of an emulsion of Water (to remove water-soluble stains) and organic solvents (to handle greases and similar organic solvent-soluble materials). The product of our invention is not only an effective emulsifying agent for such compounds, but is advantageous in obtaining the proper thickening efiect so that the final material will have the desired body and consistency. This same combination of thickening and emulsifying properties 11 has caused our product to find important uses in the thickening and stabilizing of latices.

Another characteristic of industrial importance lies in the fact that when the products of our invention are employed as textile and paper sizes, paper coatings, and the like, they produce films which are substantially water-repellent. Because of the presence of hydrophobic groups, they are considerably less easily wetted by water than the corresponding untreated polysaccharides.

Our invention results in the production of valuable laundry starches, and it has been found possible to iron fabrics containing such starches more easily and with less sticking, presumably because the fatty acid hydrophobic groups in the polysaccharide have a detackifying, lubricating effect. The water-repellent properties of such laundry starches is also of obvious value, it having been found, for example, that shirt collars, on which such starch has been used, show less tendency toward wilting.

From the description herein given of the properties of our product, further industrial uses will be apparent.

We claim:

1. A substituted polysaccharide derivative in the form of a water-dispersible material, char- 12 acterized by each substituent radical containing both a hydrophilic group and a hydrophobic group, having the following formula:

COOH

polysaccharide0 O C- R' wherein R is a radical from the class of dimethylene and trimethylene radicals and R is the substituent hydrophobic group from the class consisting of an alkyl, alkenyl, aralkyl and aralkenyl group containing from 5 to 18 carbon atoms, and wherein the carboxyl radical COOH is the hydrophilic group.

2. The substituted polysaccharide derivative of claim- 1 wherein the polysaccharide is starch.

3. The substituted polysaccharide derivative of claim 1 wherein the polysaccharide is cellulose.

CARLYLE G. CALDWELL. OTTO B. WURZBURG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,146,755 McNally et a1. Feb. 14, 1939 2,225,589 Haussman et a1. Dec. 17, 1940 2,461,139 Caldwell Feb. 8, 1949 

1. A SUBSTITUTED POLYSACCHARIDE DERIVATIVE IN THE FORM OF A WATER-DISPERSIBLE MATERIAL, CHARACTERIZED BY EACH SUBSTITUENT RADICAL CONTAINING BOTH A HYDROPHILIC GROUP AND A HYDROPHOBIC GROUP, HAVING THE FOLLOWING FORMULA: 